other booktv viewers, go to booktv.org: you can pick up the liberty amendments, you can read along, and then you can post your comments at booktv.org. it's very simple, just click on the book club tab up at the top of the page, and you'll see there there's a format for posting your comments, and you can read along all month on your own time. we'll be posting questions and comments as we go throughout the month on the liberty amendments. mark levin, thanks for your time today on booktv. >> guest: great honor, pete, thank you." >> c-span, created by america's cable companies in 1979, brought to you as a public service by your televisioning provider. >> next, robert gates at the national constitution center in philadelphia. he discussed his memoir, "duty."